Sectional heat exchangers are built up of a number of sections or segments. Sectional heat exchangers, e.g. in aluminium, exist that comprise a number of identical intermediate segments positioned next to each other; and two end segments. The number of intermediate segments that is used in the assembly of the heat exchanger depends on the required capacity of the heat exchanger. The heat exchanger has a number of channels (at least one water channel in each intermediate segment) in parallel flow connection for water to be heated, and flue gas channels extending from the one or more combustion chambers in the heat exchanger.
Examples of such heat exchangers can be found in DE102005014616B3, EP0843135A1 and WO2008/004855A2.
EP0843135A1 discloses a sectional heat exchanger wherein individual combustion chambers are created between each two segments of the sectional heat exchanger. Each combustion chamber is provided with one or more separate burners.
The segments of WO2008/004855A2 are assembled creating a heat exchanger with one combustion chamber, and with an individual burner for each intermediate segment, in order to produce flue gas for heat exchange with water flowing through the water channels of the sectional heat exchanger. The intermediate segments are assembled parallel to each other. The intermediate segments of WO2008/004855A2 can be made using extruded profiles.
A sectional heat exchanger, using cast intermediate segments, is provided in DE102005014616B3, in which one single burner can be used, mounted in the one combustion chamber of the sectional heat exchanger.
EP2080961A2 describes a boiler having a sectional heat exchanger. The sectional heat exchanger has vertical elements made of casting material for gas or oil combustion for heat exchange between hot gases and boiler water. An exhaust gas- and condensation water collector is formed in a lower area, and a combustion chamber is separated from a circular water arm. Vertical water arms are fastened to the circular water arm at water side below the combustion chamber based on a lower hub. The vertical water arms form a vertical flow channel for the hot gases.
U.S. Pat. No. 3,533,379A discloses a section boiler having grooved or channeled spaces at the interface of adjacent sections. A pliable elastic sealant, which remains substantially permanently pliable and elastic, fits the grooved or channeled spaces to join the sections. The joinder so formed is leak-proof at all ambient temperatures and flue pressures, including the flue pressures encountered in forced draft boiler systems.
It is a problem of the sectional heat exchangers of the prior art that the performance and efficiency is not optimal.